The present invention relates to a semiconductor memory device, and particularly to a semiconductor memory device using resistance variable elements.
In writing of a nonvolatile memory like a flash memory or a ReRAM (Resistive RAM), confirmation is made as to whether data has been properly written after writing of the data, and a Verify operation for performing each of additional writing operations is carried out when the data is not properly written. As the additional writing operations, normally, the operation of writing 0 is executed when it is desired to write 0, and the operation of writing 1 is executed when it is desired to write 1.
There has been described in, for example, each of Patent Document 1 and Patent Document 2, a method in which in a bipolar type ReRAM using resistance variable elements, a 0-oriented pulse of a lower voltage than usual is first applied when 1 is failed to be written, and thereafter a 1-oriented pulse is applied (second to third steps in FIG. 11, for example) to thereby perform rewriting.